Thermostatic circuit closer



' June 23, 1925.

' A. M. DE 5. GREAVES THERMOSTATIC CIRCUIT CLOSER Filed Jan. 1'7, 1922i6 fig Q 20 if ja Q Him 7 30 27 Qwuwtm cfl. (/77. 5. Greaves PatentedJune 23, 1925.

UNITED STATES PATENT OFFICE.

THEBMOSTATIG CIRCUIT CLOSER.

Application filed January 17, 1922. Serial No. 529,865.

To all whom it may concern:

Be it known that I, Ammo M. DE SILVA GREAVES, a citizen of Portugal,residing at Cambrid e, in the county of Middlesex and State ofassachusetts,.have invented new and useful Improvements in ThermostaticCircuit Closers, of which the following is a specification.

This invention relates to thermostatic circuit closers.

One object of my invention is to provide a circuit closer having animproved mounting for the thermostat per se and the circuit closingcontacts.

Another object of my invention is to provide circuit-closing contactswhich are adjustable to close the circuit at different predeterminedtemperatures.

Still another object of my invention is to provide a novel andconvenient arrangement ofa plurality of sets of circuit-closing contactsfor closing difi'erent circuits at different predetermined temperatures.

The invention consists of the features of .5 construct on, combinationand arrangement of parts, hereinafter fully described andv claimed,reference being had to the accompanying drawing, in which:

Figure 1 is a view, partly infront elevation and partly in verticaltransverse section, of a thermostatic circuit-closer embodying myinvention. Figure 2 is a side elevation of the same.

Figure 3 is a top plan view. Figure 4 is a diagrammatic view of some ofthe sets of contacts illustrating the various levels of their contactpoints.

In carrying my invention into practice, I provide a thermostatcomprising a mercur. tube 1, communicating at its lower end with a bulbor storage chamber 2 containing a supply of mercury, and having at itsupper end an expansion chamber 3. This expansion chamber 3 communicatesat its base with the bore 4 of the mercury tube, said bore beingpreferably enlarged at its point of communication with the base of thechamber 3, as indicated at 5, to permit free flow of the mercury betweensaid bore and expansion chamber.

The thermostat as thus constructed is mounted upon a suitable sup ort 6,which preferably consists of a bloc of suitable the expanded portion orexpansion chamber 3 of the thermostat, which chamber 3 is closed at itstop by the top wall of said socket 10. The socket 8 communicates withside grooves 11 and a bottom groove 12.

formed in the lower portion of the front face of the block 6, whichgrooves expose the bulb 2 to a large extent 1n order to allow,

the mercury contents thereof to be sensitively subjected to andinfluenced by atmospheric temperature conditions. Any suitable means,such as a clip 13, may be employed to detachably secure the thermostatin position upon the supporting block.

The head of the block 6 is formed with a desired number of threadedpassages 14,

leading from the top thereof down to the top of the expansion chamber 3for the reception of a desired number of b nding posts 15', forming partof a desired number of pluralities of sets of circuit closing contacts.The passages 14: and binding posts. have a threaded engagement foradjustment of said binding posts, and the binding posts of each set orworking pair are coupled to the terminal wires 16 and 17 of anelectriccircuit. Each of these wires is clamped between an adjusting andclamping ,nut 18 and a jamb nut 19, which are employed to not only clampthe associated circuit wire in position but also to clamp the associatedbinding post in adjusted position upon the supporting block.

In the present instance I have shown the use of three pairs or sets ofbinding posts 15, which form supports for an equivalent number of setsof contact points, each set comprising a pair of contacts 20 and 21extending fromthe posts downwardly into the expansion chamber 3. Each ofthese contact members comprises a metallic stem fixed at its upper endto its binding post and having with.

its lower end free and terminating at a rescribed level within theexpansion cham er, the lower ends of the contact members of each workingpair being arranged in proximity to each other so as to be connectedelectrically by contact with the mercury rising to such predeterminedlevel, whereby the circuit of which said contact members constitute thetermihals will beclosed for the energization of such circuit.

The thermostatic device and circuit closers constructed and arranged asdescribed are adapted for use in controlling a plurality of circuits,and for closing the respective circuits at difi'erent predeterminedtemperatures. F or this purpose, the lower ends of the sets of contactsforming the respective circuit terminals are arranged at differenthorizontal levels, so that the contacts of one set or the other will beconnected by the mercury as the latter rises to difierent predeterminedscale points at different temperatures. The chamber 3 permits of theexpansion of the mercury therein as it flows upwardly through theenlargement 5, to reduce the rapidity of its ascent from the time thatthe expanding mercury reaches said enlargement 5, whereby the mercury ispermitted to expand beyond the points of one set of circuit contacts andrise a distance above the same, in closing the circuit of which said setof contacts forms a part, without liabilit of prematurely contactingwith'the next liigher set of circuit closing contacts and improperlyclosing the circuit of which they form a part. In order to preventinterference between the sets of contacts, they may be grouped in acircular series, as shown, or otherwise suitably arranged to bring thepoints of each set of contacts in proper close relation, while they areat the same time not only disposed at a different level but laterallyspaced with respect to the points of the other sets of contacts. It willbe observed that while the sets of contacts are arranged at differentworking levels, the contacts of any of the sets may be verticallyadjusted, by adjustment of their binding posts, so as to regulate theworking levels of the difierent sets of contacts as desired, and so thatthe contacts of any set maybe properly adjusted to 7 dispose theirpoints in working relationship and to ensure positive connection thereofandsensitive circuit closing action when the column of mercury comes incontact there- The circuit closer constructed in accordance with myinvention may be used for many and various purposes, such as forcontrolling a fire alarm circuit, a damper governing circuit, and a fuelcontrolling circuit, and may be employed in households or other placesfor these generaluses, so that any one of a series of devices may beautomatically meats"? governed by and operated under differenttemperature conditions to perform different service actions, all of suchdevices being controlled through the medium of a single thermostaticinstrument. In practice, the block 6 may be mounted in any suitablemanner upon a wall or other proper support, or may be mounted within acasing similarly applied in position, whereby the thermostat may beenclosed and protected against liability of possible injury.

Having thus fully described my invention, I claim:

1. A thermostatic circuit closer comprising an expansion chambernormally open at its top, a relatively contracted mercu column tubecommunicating with the bottom of said chamberfa support for the chamberand tube comprising a body having in its face a seat groove receivingthe tube and having a recessed head portion receivin and closing thenormally open top of the c amber, said head portion having a partjutting outwardly beyond the expansion chamber and face of the supportbody, and circuit closing contacts extending downwardly through the headportion of the support and into the expansion chamber.

2. A thermostatic circuit closer comprising a support in the form of ablock having in its front face a partially circular longitudinal grooveand a partially circular recess intersecting the lower end of saidgroove, said block having a head portion projecting beyond said face andsaid block and'face being provided with a recess, a mercury containingbulb set in the first-named recess and having extending therefrom a merecolumn tube seated in said groove, said tube being provided at its endremote from the bulb with an expansion chamber communicating with thetop of'the tube and seated in the second-named recess, the top of saidchamber being closed by a wall at the top of the recess conjointlyformed upon the body of the block and the head and jutting forwardlybeyond the expansion chamber.

and plane of the face of the block,'and circuit closing contactsextending downwardly through the top of the block and into saidexpansion chamber.

3. A thermostatic circuit closer comprising a support in the form of ablock having in its front face a vertical lon itudinal groove and at itsupper end a hear? portion projecting forwardly beyond said face, saidblock being provided at its lower end with a cavity intersecting thelower end of the groove and at its upper end with a cavity formedpartially in the block and partially in the head portion, and said blockhaving at its lower end a bottom groove intersecting the lower recessand side grooves lead ing outwardly from said recess to the oppositesides of the block, a mercury containing uau? 6 bulb fitted in the lowerrem a' mercury chamber being closed by the top wall of the column tubeextend' upw from said upper recess, and circuit closing contacts bulband seated in sai vertical ongitudinal projecting downwardly through t ehead of I. groove, a normally open to expansion the block and throughsaid wall and into I chamber communicating with the u per end theexpansion chamber.

of the bore of the tube and 6 In said Intestimony wbereofI afi'lx my siature.

upper recess, the normally open top of 'said ABILIO M. on'SILVA GREA ES.

